What is the K.I.S.S. Rule?

KISS (“Keep it simple, stupid”) is a design principle first noted by the U.S. Navy in 1960. First seen partly in American English by at least 1938, KISS implies that simplicity should be a design goal. The phrase has been associated with aircraft engineer Kelly Johnson. The term “KISS principle” was in popular use by 1970. Variations on the phrase (usually as some euphemism for the more churlish “stupid”) include “keep it simple, silly”, “keep it simple and straightforward”, “keep it simple, soldier”, and “keep it simple, sweetie”.

Text from the Wikipedia article KISS principle, available under CC BY-SA 4.0.